uwl - work item 0000000000000 cannot be read

Dear All

I am getting error while executing R/3 based work item in uwl that is following.

Work item 000000000000 cannot be read

The same work item can be executed easily from Inbox in R/3 system.

This issue is appearing only in QA system Development works fine.

I have drawn xml comparision already and I don't find any mismatch.

any advise.

thank you

barin